Cyclic depsipeptides constitute a fascinating class of natural products. Most of them are characterized by an ester formed between the β-hydroxy function of Ser/Thr -and related amino acids- and the carboxylic group of the -terminal amino acid. Less frequent are those where the thiol of Cys is involved rendering a thioester (cyclo thiodepsipeptides) and even less common are the cyclo depsipeptides with a phenyl ester coming from the side-chain of Tyr. Herein, the preparation of the later through a cyclative cleavage using the Fmoc-MeDbz/MeNbz-resin is described. This resin has previously reported for the synthesis of cyclo thiodepsipeptides and homodetic peptides. The use of that resin for the preparation of all these peptides is also summarized.
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http://dx.doi.org/10.3389/fchem.2020.00298 | DOI Listing |
Beilstein J Org Chem
November 2021
Institute of Biological and Chemical Systems - Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology, Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
We describe the synthesis of so far synthetically not accessible 3,6-substituted-4,6-dihydro-3-pyrazolo[3,4-][1,2,3]triazines as nitrogen-rich heterocycles. The target compounds were obtained in five steps, including an amidation and a cyclative cleavage reaction as key reaction steps. The introduction of two side chains allowed a variation of the pyrazolo[3,4-][1,2,3]triazine core with commercially available building blocks, enabling the extension of the protocol to gain other derivatives straightforwardly.
View Article and Find Full Text PDFChem Commun (Camb)
August 2021
Università degli Studi di Milano, Dipartimento di Chimica, via C. Golgi, 19, Milan, I-20133, Italy.
Cyclative cleavage of an amine-carbamate self-immolative spacer to deliver a hydroxyl cargo was inhibited by spacer derivatisation with a phosphate monoester handle. This trifunctional spacer was installed in a model anticancer prodrug that showed fast drug release only when incubated with both a protease and a phosphatase enzyme.
View Article and Find Full Text PDFFront Chem
April 2020
CIBER-BBN, Networking Centre on Bioengineering, Biomaterials and Nanomedicine, University of Barcelona (UB), Barcelona, Spain.
Cyclic depsipeptides constitute a fascinating class of natural products. Most of them are characterized by an ester formed between the β-hydroxy function of Ser/Thr -and related amino acids- and the carboxylic group of the -terminal amino acid. Less frequent are those where the thiol of Cys is involved rendering a thioester (cyclo thiodepsipeptides) and even less common are the cyclo depsipeptides with a phenyl ester coming from the side-chain of Tyr.
View Article and Find Full Text PDFMolecules
April 2018
Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, Hnevotinska 5, 779 00 Olomouc, Czech Republic.
The preparation of 5-methylene-thiohydantoins using solid-phase synthesis is reported in this paper. After sulfonylation of immobilized Ser (-Bu)-OH with 4-nitrobenzenesulfonyl chloride followed by alkylation with various bromoketones, the 4-Nos group was removed and the resulting polymer-supported α-acylamino ketones reacted with Fmoc-isothiocyanate. Cleavage of the Fmoc protecting group was followed by the spontaneous cyclative cleavage releasing the 5-methylene-thiohydantoin derivatives from the polymer support.
View Article and Find Full Text PDFOrg Lett
June 2017
Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China.
A rhodium-catalyzed regioselective C-H activation/cyclization of azoxy compounds with alkynes has been disclosed to construct a variety of 2H-indazoles. A [4 + 1]-cycloaddition rather than a normal [4 + 2] mode is observed in the process of cyclative capture along with an oxygen-atom transfer and a C≡C triple bond cleavage. This protocol features a broad substrate scope, a good functional group tolerance, and an exclusive regioselectivity.
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